


i'm sure it's nothing but some heartburn, baby

by noahczernys



Category: Haikyuu!!
Genre: 170221: new edit bc my no beta tag aged poorly, Alternate Universe - College/University, Fluff, Love Confessions, M/M, Pining, atsumu is a smitten loser, edited for cousin komori inclusion fkldshsdfkhjl, i guess??, no beta we live life on the wild side, sakusa has same face syndrome, the gekkan shoujo nozaki kun au no one asked for, who listens to carly rae jepsen no im not projecting
Language: English
Status: Completed
Published: 2020-05-12
Updated: 2020-05-12
Packaged: 2021-03-02 17:01:51
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,871
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24140263
Author URL: https://archiveofourown.org/users/noahczernys/pseuds/noahczernys
Summary: The last thing Atsumu expects to get out of this confession is a fucking autograph.
Relationships: Miya Atsumu/Sakusa Kiyoomi
Comments: 18
Kudos: 270





	i'm sure it's nothing but some heartburn, baby

**Author's Note:**

> the title is from 'happy not knowing' from carly rae jepsen's dedicated! it's a banger, pls listen to it

The last thing Atsumu expects to get out of this confession is a fucking autograph.

Not when he had it perfectly planned with a practiced segue to the confession down to the mere timing of it. The sunset always filters in through the windows of their classroom and casts an amazing amber glow over everything that would definitely help his case here by spicing up the ambience. Or so he thought.

Because here he stands in front of Sakusa Kiyoomi, shoulders slightly slumped as he stares at the autograph torn from Kiyoomi’s notebook moments earlier.

  
  


_Thank you for your support._

_ > Hirose Nanako _

  
  


Atsumu squints at the characters that definitely do not spell Kiyoomi’s name and wonders why the name rings a bell regardless. He’s promptly drawn away from his thoughts when Kiyoomi clears his throat and adjusts his face mask, clearly making his move to leave.

“If you’ll excuse me…”

“Wait!” Atsumu doesn’t expect Kiyoomi to actually listen, let alone turn around with a raised brow that has him forgetting what he was going to say for a moment. Now that all of the potential scenarios he came up throughout the day with have been thrown out the window, all Atsumu can come up with is, “That, uh, wasn’t what I meant.”

“Oh.” With the mask, it’s difficult to decipher Kiyoomi’s expression which had been hard to read to begin with. But his gut tells him to be hopeful because of the lilt in Kiyoomi’s tone.

“Yeah, so—”

“I suppose you can come over,” Kiyoomi suddenly, then narrows his eyes at Atsumu. “You showered today, right?”

Heart racing in his chest, Atsumu has no time to question his choice in men. He doesn’t even have the gall to reply with words, opting to nod instead and hastily picking up his bag when Kiyoomi begins to walk away after letting out a hum that Atsumu guesses means he’s got the seal of approval.

If Kiyoomi notices the satisfied look on Atsumu’s face, he doesn’t bring it up. Rather, he doesn’t bring much up save for voicing out his dislike for the nickname Atsumu came up with. It’s clear that Kiyoomi isn’t much of a talker, leaving Atsumu somewhat confused and also alone with his thoughts. In hindsight, maybe going home with someone who he’s only spoken to a handful of times and handed him an autograph with a fake name in response to a confession isn’t Atsumu’s smartest move. He quickly extinguishes any doubt he harbours because _hell_ , he’s going home with Sakusa Kiyoomi.

Admittedly, the fake name only adds to the enigma that is Kiyoomi.

It's kinda hot.

Naturally, he sends a quick text to Osamu.

To: the lesser twin

> i win  
> ya owe me :P

That should work.

It’s only when they reach Kiyoomi’s apartment does Atsumu remember to bring it up.

“Hey Omi-kun, just who exactly is…” He trails off when his gaze lands on the book resting on the table by the doorway. 

_The Diary of Us by Hirose Nanako_

“Just set your bag down there.” Kiyoomi emerges from the kitchen with two mugs of tea and nods towards the dining table where stacks of paper, bottles of ink, and pens are neatly laid out. Atsumu had been too caught up thinking about that book to notice that he’d been left alone standing in the living room like a fool.

When it all clicks, it takes all of Atsumu’s willpower not to drop dead from the sheer embarrassment. A fool would be an understatement.

Let this be the last time he ever trusts his gut instinct.

Atsumu takes the seat across from Kiyoomi, unable to draw his stare away from Kiyoomi’s face due to the shock of finding out he’s behind one of the current bestselling shoujo manga series, as well as how _good_ he looks with his mask off. 

God, Osamu is never gonna let him live this down.

“Is something wrong?” Kiyoomi’s looking at him now and Atsumu has to look away before he starts blushing. He looks at the sheet in front of him, then picks up the pen he thinks he’s meant to use.

“No, I just never worked with this before.” Atsumu says in place of _I have no fuckin’ clue what I’m doin’ here._

Kiyoomi sighs, but leans forward anyway to point at the x’s marked on the drawings with the tip of his pencil. He has two moles on his wrist and a barely noticeable one on his middle finger, Atsumu notices.

“Fill in whatever is marked with an x.”

“That’s it?” Atsumu looks back down at the page, then back at Kiyoomi. “What if I screw it up?”

Sure, he may be the (self-proclaimed) pride of their university’s visual arts department, but this is vastly different from his usual oil paints and canvases. Something also tells him that Kiyoomi would look rather terrifying if angered and while the imagined sight would add to the list of things that makes Kiyoomi kinda hot, Atsumu doesn’t really want to find out any time soon.

“You won’t. I’ve seen your work,” is all Kiyoomi says before getting back to his own work, signalling the end of the conversation. That’s all it takes to boost Atsumu’s confidence again so he picks up the pen and begins to colour within the lines.

“One more question.”

“Hm?”

“Can I call you Nanako—”

“No.”

  
  
  


—

  
  
  


After working with Kiyoomi for two months, Atsumu likes to think he knows the guy pretty well by now. He’d even go as far to say that they’re friends at this point, which is not as far as Atsumu hoped to get but patience is a virtue and while Osamu doesn’t think so, he believes he can be virtuous if needed.

However, they aren’t as close as Kiyoomi is with Komori, who’s in charge of the elaborate backgrounds in The Diary of Us, and jealousy begins to rear its ugly head. Atsumu also has a feeling that the protagonist of the manga is based off Komori to some extent but he can never bring himself to ask Kiyoomi if it’s true and what that means.

Instead, he pesters Osamu about it at least once a week after learning that his twin shares a class with Komori.

Osamu rolls his eyes when Atsumu brings it up before leaving to meet up with Kiyoomi. “Just ask him, dumbass.”

There's a funny glint in Osamu's eyes that goes away as quickly as it appeared, but Atsumu brushes it off as something trivial.

“‘Samu, I can’t just ask him!”

“It’s not like he’ll fire you. Not that you get paid anyway,” Osamu mumbles the last bit around his sandwich, unaffected by Atsumu’s petulant scowl.

“You're no help. Absolutely useless. I dunno why I even bother.”

“It's desperation, loser. That’s why.”

“I hope you choke, asshole.”

“Maybe you should sell the autograph he gave you. Y’know, when he totally misread your confession and thought you were some random fan. Probably still does. Should I ask Komori?”

“Choke!” Atsumu flips him off before closing the door behind him, stuffing his hands in his pockets as he walks down the stairs to leave their apartment building.

It’s a chilling, ten-minute walk to the coffee shop they agreed to meet at. From what Atsumu’s gathered, it’s the only coffee shop Kiyoomi frequents and he figures it’s got something to do with how Kiyoomi essentially has a booth reserved in the back with the perfect angle for people watching. Unsurprisingly, he’s already there when Atsumu waltzes in, cradling his usual cappuccino in his own tumbler while Atsumu orders his hot chocolate. Caffeine in this hour would most definitely keep him up all night, and while Kiyoomi doesn't seem to have any qualms with that, Atsumu's relatively normal sleep schedule is the only normal thing about his life so far.

Atsumu finds that it’s easy to fall into routines with Kiyoomi and didn’t even realise just how many they’ve built in the span of two months until Osamu and Rintarou pointed it out the other day. From these coffee shop hangouts to the way Atsumu's started to carry around a bottle of Kiyoomi's favourite brand of hand sanitiser, prepared for the unlikely day that Kiyoomi forgets his own. Knowing him better now, falling in love feels more like tripping over a stone and tumbling headfirst into a brick wall.

A brick wall of love.

And it fuckin' hurts.

Atsumu slides into the booth, careful not to spill his drink all over the table, and offers Kiyoomi a crooked grin that gets a quick glance at most. Atsumu knows better than to take it to heart.

“Already getting a headstart?” He glances at the small sketchbook in Kiyoomi’s hand, mechanical pencil in the other creating haphazard strokes on the paper that Atsumu knows will end up looking better than the shit he’ll come up with. 

Kiyoomi hums, gaze flitting to the couple sitting three tables away from them then back to his notepad, brows furrowed in concentration. Atsumu has long accepted that Kiyoomi just makes dark circles look good for once, even if he can’t pull off the look himself.

Taking a sip from his hot chocolate, he stretches his arms over his head before whipping out a multi-coloured pen and a mini notepad from the pockets of his coat. Frankly, Atsumu isn’t sure why he’s here when he doesn’t have much say in anything except for inking, especially after that time he pointed out that Kiyoomi’s got same face syndrome for his manga’s side characters. 

That was the day Atsumu learned Kiyoomi isn’t above stooping down to his level of pettiness, though he wields it with much more subtlety than Atsumu does.

However, when Kiyoomi had first asked him to tag along, there was no way Atsumu was going to turn him down. Even though they don’t talk as much in these sessions—Atsumu refuses to call them dates _just yet_ —because Kiyoomi can’t stand to be interrupted when he’s in the zone, Atsumu never felt the need to decline until it became a new routine.

While Kiyoomi’s pages often end up filled with characters inspired by the people surrounding them and notes in the margins, Atsumu’s pages involve a myriad of doodles in red, black, and blue ink with the occasional quick sketch of the man sitting opposite of him. He makes sure to cover those with his arm.

Halfway through a warped drawing of the ginkgo tree outside the coffee shop, Atsumu’s phone buzzes in his pocket.

From: the lesser twin

> did you ask him yet

Atsumu chews at the top of his pen as he types out a reply.

To: the lesser twin

> im on it

From: the lesser twin

> sure lol  
> confess to him while you’re at it

He doesn’t entertain Osamu with a reply, placing the phone on the table screen-down with a scoff. With Kiyoomi very much invested in his sketchbook, Atsumu knows better than to bother him and possibly reveal his insecurities so he bites his tongue and focuses on his own notepad. It goes well for a good five minutes until he realises his thoughts are being projected onto the paper and there’s no way he can show Kiyoomi his work now.

“Atsumu.” Kiyoomi’s still looking down at the paper, but his hand has slowed down to make room for conversation. “I can hear you thinking.”

“Are you datin' Komori?” Atsumu blurts out, heart hammering in his chest when Kiyoomi’s hand stills.

But Kiyoomi defies his expectations yet again and instead of scathing words, he lets out a snort. Heat creeping up to his cheeks, Atsumu can only watch, mouth slightly ajar in wonder, as Kiyoomi attempts to stifle his laughter.

When he finally regains his composure, Kiyoomi runs a hand through his hair to fix his curls before giving Atsumu a pointed look. “He's my _cousin_. What gave you that idea?”

_Osamu, you son of a bitch._

“Keiko is based on him, right?” Atsumu asks in place of an answer to Kiyoomi’s question, embarrassed enough as is. He can only hope it doesn’t show.

Kiyoomi nods, picking up his pencil that slipped from his grip earlier. Without another word, he gets back to work. Atsumu’s phone buzzes again and he caves into the temptation, turning it over only to glare at Osamu’s recent texts. Twin telepathy is a bitch.

_Fine_ , he’ll show Osamu. Now that he knows that Kiyoomi and Komori are not dating, his confidence slowly makes its return.

He’s got this.

Taking a large gulp from his drink, Atsumu clears his throat.

“Omi-kun.” 

Kiyoomi looks at him, clearly unamused by another interruption with the use of his nickname. Atsumu stumbles over his words, suddenly finding great interest in the water stain on the window beside him.

“I really like your work.”

_For fuck’s sake, Atsumu._

Kiyoomi raises a perfectly arched brow.

“Thanks? Though I already assumed you did since it’d be strange to work with me otherwise.”

Atsumu’s phone lets out another mocking buzz and he can already hear Osamu wheezing with laughter.

“Just wanted to let you know,” Atsumu slaps on a teasing grin when he eventually looks back at Kiyoomi. “Even if you got same face syndrome, I still like your work, Omi-kun.”

Kiyoomi’s curious stare morphs into a glare. Atsumu’s grin widens even though he gets flipped off and ignored for a sketchbook. He knows he’s got it bad when he begins wishing that he was the sketchbook in Kiyoomi’s hand—the mechanical pencil would work too.

When Kiyoomi leaves him to his own devices to get another refill, Atsumu takes the opportunity to slam his head on the table with a defeated groan.

  
  
  


—

  
  
  


They’re five months into this arrangement when Atsumu feels something akin to enlightenment for the first time. 

He spent the past three weeks toiling over final projects for his course and therefore, hardly saw Kiyoomi, who told Atsumu to focus on his projects and that he could work on the inking himself alongside preparing for his own astronomy exams ( _astronomy, how mysterious!_ ). Since he stood his ground and wouldn’t take no for an answer, Atsumu had no choice but to relent and spend three weeks solely communicating with Kiyoomi via texting.

Those three weeks didn’t do shit to purge his feelings. In fact, Atsumu is sure his pining has gotten worse now, the three-week drought having amplified his crush even more if possible. Putting a pause on their routines didn’t help either.

Leave it to Kiyoomi to constantly defy his expectations.

As soon as he tells Kiyoomi that he’s done with everything, they fall back into their routine and Atsumu trips over the shoes in his doorway twice before finally making it out to walk to Kiyoomi’s place.

So said enlightenment comes in the form of none other than Sakusa Kiyoomi greeting him at the door with his hair tied into a short ponytail, headphones resting around his neck, and his bangs clipped back with colourful bobby pins.

_When did his hair get this long?_

Frazzled by the sight, Atsumu’s brain-to-mouth filter decides to stop working then and there.

“Aw, you look cute, Omi-omi,” is what he says in lieu of a normal greeting and a part of him wishes that Kiyoomi would just slam the door in his face to knock the new memory out of him.

That is, until Kiyoomi’s ears and neck start to redden despite his deadpan stare and Atsumu decides this isn’t a scene worth sacrificing. He bites down on his tongue before his brain betrays him any further.

“You have a ketchup stain on your shirt,” is all Kiyoomi says before he turns to head back to the table.

Atsumu makes a disgruntled sound and at his shirt to find the stain, pouting when he does. He switches his shoes for his usual pair of house slippers and takes his spot opposite of Kiyoomi, pages and equipment already neatly laid out for him on his side of the table.

The panels look a lot different than what they were working on before Atsumu had to focus on his projects. “These new? I thought Akaashi-san extended the deadline.”

“I had a sudden burst of motivation in the middle of one of my exams, so I powered through most of it pretty quickly.” 

Well, that explains the bandages wrapped around Kiyoomi’s right index finger and middle finger.

Atsumu clicks his tongue. “I coulda helped a little.”

“You had your projects to work on.” Kiyoomi says with a pointed stare.

“I told you I finished early.”

“Tobio said he saw you running to campus on submission day. He sent me a video of what happened with the lamp post.”

Atsumu gapes at Kiyoomi when he snickers at that, at _him_.

“He was there?! He didn’t even help!” Atsumu whines, embarrassed and defeated yet again. It’s beginning to feel like a recurring trend at this point.

Kiyoomi laughs again and Atsumu feels compelled to record it, but he doesn’t because that would be weird. And creepy. He tries to commit it to memory instead.

“Kinda glad he didn’t. Otherwise I wouldn’t have that video.”

“Can I at least see it? Maybe I look good running headfirst into a pole,” Atsumu shoots him a smug smile. “Is that why you’re glad he didn’t help out?”

“Sure, you tell yourself that, Atsumu,” Kiyoomi snorts before glancing down at his work. “I’ll show you after you’ve finished.”

When a comfortable silence settles around them as they start working, Kiyoomi puts his headphones back on after asking Atsumu if he minds. He doesn’t and when the white noise gets a little hard to bear alone, Atsumu puts in his airpods.

He doesn’t know how much time has passed since they started, but he does know that he’s gone through Carly Rae Jepsen’s Emotion Side B thrice now. Deciding to take a short break, Atsumu sets his pen down and cracks his knuckles before standing up to stretch his legs.

“Omi-kun, I’m gonna get something to drink.”

Unsurprisingly, his words don’t shake Kiyoomi out of this concentrated state. Atsumu walks to the fridge anyway, plucking out a bottle of green tea for himself and a bottle of oolong for Kiyoomi. 

Taking a sip from his bottle, Atsumu lets his gaze wander around the apartment from the kitchen until it lands on Kiyoomi. He doesn’t know if it’s because of the new hairstyle or the album he listened to three times in a row, but the weight of his feelings for Kiyoomi is much heavier now. So much so that he’s filled with the urge to wax poetic about Kiyoomi’s new hairstyle that looks stupidly good on him. It’s unfair really.

Atsumu sighs and sits back down, sliding the unopened bottle towards Kiyoomi before dragging his hands down his face with a groan. He peeks through his fingers to see if that got a reaction out of Kiyoomi. 

It didn’t. 

He remains focused on his work, looking pretty and unbothered, while Atsumu has a mini crisis right in front of him _over him_. Hell, he isn’t even bopping his head to whatever he’s listening to like a normal person would.

“Bastard,” Atsumu mutters, glancing at Kiyoomi only to be met with nothing again. He lets his hands fall from his face to rest on the table and watches Kiyoomi work, seemingly oblivious to Atsumu’s scowl.

“You’re really killin’ me over here, Omi-kun. I don’t even know why I like you so much.”

Atsumu freezes. That came out much louder than he intended.

When he notices the red creeping up Kiyoomi’s neck, it occurs to Atsumu that Kiyoomi isn’t drawing anymore.

Then it dawns on him.

“Oh my god, were you even listening to anything?!” Atsumu practically screeches, which gets a grimace from Kiyoomi who takes off his headphones.

“My phone died a few minutes ago.”

At a loss for words, Atsumu can only let out a string of incomprehensible nonsense before opting to slam his head down on the table because that seems like a better option than explaining himself. It hurts less, that’s for sure.

“Can you just pretend you didn’t hear that? Like pretend those were song lyrics, y’know?” 

He hears Kiyoomi sigh followed by the screech of his chair sliding against the floor. For a moment, Atsumu wonders if Kiyoomi went somewhere else to leave him to wallow in self-pity until he senses a presence beside him. He still can’t bring himself to lift his head up just yet.

As Kiyoomi moves the jars of ink away from Atsumu’s head, he softly asks, “Did you mean it?” 

“I told you to forget it,” Atsumu mumbles into the paper.

“Atsumu.”

_Do not give in, Atsumu._

Kiyoomi lets out an exasperated sigh.

“ _Tsumu_ , I’m not gonna say it until you look at me.”

“Well fuck, obviously I’m gonna...” Atsumu starts when he lifts up his head, only to forget what he was going to say when he realises Kiyoomi moved his chair to sit beside him and his blush still hasn’t disappeared. In fact, this is probably the first time Atsumu has seen Kiyoomi look so unsure of himself.

“Did you mean it?” Kiyoomi doesn’t meet his gaze when he asks again.

Atsumu caves in. “Yeah. I meant it the first time too. Is that gonna be a problem—”

“The first time?”

“Y’know, in the classroom? When you gave me your autograph. God, Omi-kun, do you have to make me bring it up again?” Instead of using the table, Atsumu decides to lean back on his chair and cover his face with his hands again to mask the embarrassment.

There’s a beat of silence before Kiyoomi interrupts it with, “Oh.”

Then Atsumu hears the tell-tale sound of a shitty attempt to stifle laughter and brings his hands down to see Kiyoomi covering his mouth with the back of his hand, his laugh slipping past regardless.

“It’s not funny!” Atsumu frowns, bottom lip jutting out into a pout because even though he’s being laughed at, he can’t really complain when Kiyoomi looks like that.

“Sorry. I’m sorry, I just…” Kiyoomi trails off, but keeps his eyes trained on Atsumu, a small smile playing on his lips. “I like you too, Atsumu.”

“You’re serious?”

Kiyoomi rolls his eyes, though his smile never leaves his face. “Yes, I’m serious.”

Atsumu’s brows furrow. “Please don’t say sike.”

“I’m not gonna say sike. Anyways, you've got something on your face,” Kiyoomi says before Atsumu can even get a reply out, only to press a chaste kiss on his lips. This time, Kiyoomi is the one who covers his face while Atsumu takes his time to process what just happened.

“ _Jeez_ , Omi-kun.” A shiteating grin spreads across Atsumu’s face when he gently pries Kiyoomi’s hands away from his blushing face, thumbs rubbing slow circles over his wrists. “I guess you really are a shoujo mangaka. You should include that in the next chapter.”

“I take it back.”

“That was pretty smooth. I guess I shouldn’t have expected any less from the great Hirose Nanako.”

“You really do have an inkstain on your forehead though. And I will say sike if you don’t stop.”

“Omi-kun!”

**Author's Note:**

> was actually planning on writing something angsty based off night shift by lucy dacus, but then i got tipsy, rewatched gsnk and listened to dedicated (2019) so u kno i had to do it to them
> 
> this is my first fic (if that wasn't obvious lmao) and there's def some ooc-ness in there, so thank u for reading and pls leave kudos/a comment if u liked it :*
> 
> also feel free to follow my [twitter](https://twitter.com/MAKIZENlNS) for more sakuatsu brainrot <3


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